062111 - Application of Underground Distribution Transformers...Bushings and 3 Secondary Bushings Including the Insulated Neutral (see ANSI/IEEE Type 2(a) per IEEE C57.12.25) − Self-Protected

UG-1: TransformersGreenbook

EDM

Rev. #26: 12-01-19 062111 Page 1 of 26

Electric Distribution

062111

ConstructionFunction:Asset Type:

Issued by: Date:Michael Thibault (MLTC) 12-01-19

Rev. #26: This document replaces PG&E Document 062111, Rev. #25. For a description of the changes, see Page 26.

APPLICATION OF UNDERGROUND DISTRIBUTION TRANSFORMERS

Prepared by: ABB1

Purpose and ScopeThis document provides a convenient reference for the types of transformers that are purchasable and used forunderground distribution. The available voltages and kVA ratings are indicated along with the applicable codes tofacilitate ordering.General Information

1. To conserve space and avoid overlap with other documents, the description of transformers shown has beenshortened. Individual characteristics of these transformers such as dimensions, accessories, and protectioncan be determined by making reference to the application documents.

2. ApplicationA. Single-Phase: The standard transformer for single-phase service is the Style DF-LB, single-phase, pad-mounted

transformer (see Table 1 through Table 3 on Page 5). The 25 kVA through 100 kVA sizes are used for newconstruction. The 167 kVA size is reserved for replacement use, to solve loading or voltage problems. Where theiruse is required, several other types may be available with the required voltage and kVA ratings.(1) Chester area pad-mount transformer (see Table 4 on Page 5).(2) Subsurface horizontal transformer (see Table 5 and Table 6 on Page 6).(3) Subway-LB transformer (see Table 8 on Page 7).

B. Three-Phase: The standard transformer for three-phase service is Style MTP, Style IIE-LB, or Style IIGpad-mount transformer (see Table 12 through Table 19 on Pages 8 through 10). Where their use is required,several other types may be available with the required voltage and kVA ratings.(1) Duplex-LB pad-mount transformer (see Table 9 on Page 7).(2) Duplex subsurface transformers (see Table 21 on Page 10).(3) Radial dead-front transformer (see Table 18 on Page 10).(4) Style IIC transformer (see Table 20 on Page 10).(5) Style IIH transformer (see Table 41 on Page 16).

(6) UCD-LB transformer (see Table 22 on Page 11).

C. “-LB” designation means that the transformer has the following characteristics:

(1) Uses bayonet fuses.

(2) Has backup current-limiting (CL) fuses.

(3) Has a load-break switch between bayonet and CL fuses.

(4) Will accommodate load-break elbows.

3. For replacement options of older style transformers, see Document 068195 for recommendations.

4. See Document 072149 for when to use pad-mount, subsurface, or vault-type transformers.

5. Each transformer code has been assigned a footnote indicating the desired use of the transformer asdefined below:

A. “1 − Current Standard Design and May Be Purchased” - these are transformers with the most current type,size, and voltage rating and are regularly purchased and used.

B. “4 − Use for Replacement Only and May Be Purchased” - may be purchased as required for replacements.They should not be used for new construction.

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UG-1: TransformersGreenbookEDM

Application of Underground Distribution Transformers

Rev. #26: 12-01-19062111 Page 2 of 26

C. Transformers coded with an “E” are included in emergency stock.

D. Transformers coded as 1 are available for use on new business jobs.

E. Transformers coded as 4 are to be used only when required to replace an existing installation.

6. Transformers indicated as “stainless steel” have all exterior metal parts (unless otherwise noted in the referenceddocuments) fabricated out of stainless steel or other material of equal or superior corrosion resistance. These unitsshall be used whenever a transformer is to be installed in the severe or moderate corrosion areas of Document 032911. Stainless steel units should also be used whenever local experience has determined thattransformers experience accelerated corrosion leading to early replacement.



EDMApplication of Underground Distribution Transformers

Rev. #26: 12-01-19 062111 Page 3 of 26

Table of ContentsTable/Figure Page No.

Types Suitable for New ConstructionSingle-Phase:

• Pad-Mount Style DF-LB Table 1 − Table 3• Pad-Mount Chester Area Table 4 5• Subsurface, Horizontal Table 5 − Table 6 6• Subsurface, Round Table 7 6• Subsurface, Subway-LB Table 8 7

Three-Phase, Pad-Mount:• Duplex-DF Table 9 7• Style MTP Table 10 − Table 11 7• Style IIE-LB Table 12 − Table 17 8−9• Radial Dead-Front Table 18 10• Style IIG Table 19 10• Style IIC Table 20 10

Three-Phase, Subsurface:• Duplex Table 21 10• UCD-LB Table 22 11

Specialty TransformersThree-Phase, Subsurface :

• Network Table 23 − Table 25 11Three-Phase, Dry Type:

• Network Table 26 − Table 27 12Three-Phase, Pad-Mount:

• Network Table 28 12• System Tie Table 29 − Table 30 12• Grounding Bank Table 31 13• Zigzag-Radial Dead-Front Table 32 13

Types for Replacements OnlySingle-Phase:

• Pad-Mount Live-Front, Clam Shell Table 33 −Table 34 13−14• Subsurface, Round Table 35 − Table 37 14−15

Three-Phase, Pad-Mount:• Style IIC Table 38 15• Style IIF Table 39 − Table 40 15−16• Style IIH Table 41 16• Radial, Dead-Front Table 42 16• Radial, Live-Front Table 43 − Table 44 17

Three-Phase, Subsurface Vault Table 45 17Transformer Winding Designations Table 46 − Table 47 18−19Transformer Insulating Fluid Table 48 19System Primary Voltages Table 49 20Pictorial Index Figure 1 − Figure 6 21−26



Rev. #26: 12-01-19062111 Page 4 of 26

References Location DocumentCabinet and Transformer for Single-Phase 12 kV Pad-Mounted Transformer Installation Underground Residential Areas ELS 032732. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Corrosion Area-Overhead Lines OH: General/EPM 032911. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Requirements for Conventional Three-Phase Small Power Transformers ELS 033705. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Single-Phase, Subsurface, Round Transformers UG-1: Transformers 035313. . . . . . . . . . . . . . . . . . . . . . .Underground Commercial Distribution, Three-Phase, Subsurface Transformer UG-1: Transformers 039830. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Live-Front, Low-Profile, Single-Phase, Pad-Mounted Transformers UG-1: Transformers 042761. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cabinet and Transformer for Low-Profile, Single-Phase, 6.9 kV Pad-Mounted Transformer Installation Underground Residential Systems ELS 042764. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Radial, Three-Phase, Pad−Mounted Transformers UG-1: Transformers 043816. . . . . . . . . . . . . . . . . . . . .Loop-Style, Three-Phase, Pad-Mounted Transformers UG-1: Transformers 045290. . . . . . . . . . . . . . . . . .Pad-Mounted Network Transformer UG-2: Transformers 045774. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Open Wye to Zigzag Wye Transformation Equipment and Connection UG-1: Transformers 045786. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Three-Phase, Pad-Mounted Autotransformer UG-1: Transformers/EPM 051119. . . . . . . . . . . . . . . . . . . . .Duplex-Type, Three-Phase, Subsurface Transformer UG-1: Transformers 051776. . . . . . . . . . . . . . . . . . .Horizontal, Single-Phase, Subsurface Transformers UG-1: Transformers 060578. . . . . . . . . . . . . . . . . . .Pad-Mounted Ground Fault Sensing for Cogeneration UG-1: General 062264. . . . . . . . . . . . . . . . . . . . . . .Single-Phase, Dead-Front, and Duplex, Pad-Mounted Transformer UG-1: Transformers 064307. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 kV Circuit Supply UG-1: Transformers 068184. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Distribution Transformer Replacement Options UG-1: Transformers/EDM 068195. . . . . . . . . . . . . . . . . . .Three-Phase Subsurface Network Transformers UG-2: Transformers 072137. . . . . . . . . . . . . . . . . . . . . . .Three-Phase Subsurface Vault Transformers UG-2: Transformers 072138. . . . . . . . . . . . . . . . . . . . . . . . . .Single-Phase Subway Transformers UG-2: Transformers 072139. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pad-Mount Transformers-Style IIG and Style IIH UG-1: Transformers 072146. . . . . . . . . . . . . . . . . . . . . . .Selection of the Type of Underground Equipment UG-1: Transformers/Greenbook 072149. . . . . . . . . . . .Engineering Material Specification #86, “Single-Phase, and Three-Phase Pad-Mounted Distribution Transformers” TIL EMS 86. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Engineering Material Specification 91, “Single-Phase and Three-Phase Subsurface Distribution Transformers TIL EMS 91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Rev. #26: 12-01-19 062111 Page 5 of 26

Single-Phase, Pad-Mount, for New Construction

Table 1 Codes for Style DF-LB, 1-Wire (2-Bushing) No Loop Switches With Transformer Switch With 2 PrimaryBushings and 3 Secondary Bushings Including the Insulated Neutral (reference Document 064307 andSpec. 86) − Self-Protected

kVA

20,780GRDY/12,000

240/120 V

Mild Steel Stainless Steel

25 261501 1 262890 1

50 261502 1 262891 1

100 261503 1 262892 1

167 261504 4, E 262893 4, E

Table 2 Codes for Style DF-LB, 2-Wire, (4-Bushing) No Loop Switches With Transformer Switch With 4 Primary Bushings and 3 Secondary Bushings Including the Insulated Neutral (reference Document 064307 and Spec. 86) − Self-Protected

kVA

12,000/20,780GrdY 17,200 20,780

240/120 V 240/120 V 240/120 V

Mild Steel Stainless Mild Steel Mild Steel

25 261507 1 261519 1 261511 1 261515 1

50 261508 1 261520 1 261512 1 261516 1

100 261509 1 261521 1 261513 1 261517 1

167 261510 4 261522 4, E 261514 4, E 261518 4, E

Table 3 Codes for Style DF-LB, 3-Wire, (6-Bushing) No Loop Switches With Transformer Switch and With6 Primary Bushings and 3 Secondary Bushings Including the Insulated Neutral (referenceDocument 064307 and Spec. 86) − Self-Protected

kVA

2,400/4,160GrdY 4,160 x 12,000

12,000/20,780GrdY 17,200 20,780

240/120 V 240/120 V 240/120 V 480/240 V 240/120 V 240/120 V

Mild SteelMildSteel Stainless

MildSteel Stainless Mild Steel Mild Steel Mild Steel Stainless

25 − − − 261531 1 261543 1 262721 1, E 261535 1 261539 1 262894 1

50 − − − 261532 1 261544 1 − 261536 1 261540 1 262895 1

100 262043 1, E 261785 1 261988 1, E 261533 1 261545 1 − 261537 1 261541 1 262896 1

167 − − − 261534 4 261546 4, E − 261538 4, E 261542 4, E 262897 4, E

Table 4 Codes for Chester Style Specialty Transformers - Single-Phase, Pad-Mount, Load-Break,Dead-Front With Single-Phase Cabinet for Use in the Chester, CA Area. With 2 PrimaryBushings and 3 Secondary Bushings Including the Insulated Neutral (see ANSI/IEEE Type 2(a)per IEEE C57.12.25) − Self-Protected

kVA12,470GrdY/7,200 − 240/120 V

Mild Steel

50 017414 1, E

100 −1 Current standard design and may be purchased.23

4 Use for replacement only and may be purchased.E Included in Emergency Stock5









Rev. #26: 12-01-19062111 Page 6 of 26

Single-Phase, Subsurface, for New Construction

Table 5 Codes for Subsurface Horizontal, Single-Phase With 4 Primary Bushings With 2 (25-50 kVA) or 4 (75-167 kVA) Hot Secondary Leads. Neutral Lead May Be Permanently Grounded. (referenceDocument 060578 and Spec. 91) − Self-Protected, Stainless Steel

kVA

12,000/20,780GrdY240/120 V

17,200240/120 V

20,780240/120 V

No Switch

With Single-PhaseSwitch

No Switch No Switch With Single-Phase Switch

25 262389 1 − 262395 1 262436 1 −

50 262391 1 − 262396 1 262437 1, E −

100 262393 1, E 013884 1, E 262397 1 262438 1, E 262439 1, E

167 262394 4, E 262181 4, E 262398, 4, E 263050 4 E −

Table 6 Codes for Subsurface Horizontal, Single-Phase With 6 Primary Bushings With 2 (25-50 kVA) or 4 (75−167 kVA) Hot Secondary Leads. Neutral Lead May Be Permanently Grounded. (referenceDocument 060578 and Spec. 91) − Self-Protected, Stainless Steel

kVA

12,000/20,780GrdY240/120 V 17,200 − 240/120 V 20,780 − 240/120 V

No SwitchWith

Three-PhaseSwitch

No SwitchWith

Three-PhaseSwitch

No SwitchWith

Three-PhaseSwitch

25 260328 1 027264 1, E 261106 1 − 261102 1 −

50 260668 1, E − 261107 1, E − 261103 1, E −

100 260882 1, E 027266 1, E 261108 1 027269 1, E 261104 1, E 027267 1, E

167 261000 4, E − 261109 4, E − 261105 4, E −

Table 7 Codes for Subsurface Round, Single-Phase With 3 Secondary Bushings, Neutral May bePermanently Grounded. Use to Supply Single-Phase Load.(reference Document 035313 and Spec. 91) − Self-Protected, Stainless Steel

kVA

4160/7200Y240/120 V

4 Primary Bushings

4,160GrdY/2,400240/120 V

2 Primary Bushings

No Switch No Switch With Single-Phase Switch

100 262371 1, E 262120 1, E 262143 1, E

(See Table 36 on Page 14 for other single-phase round transformers.)

1 Current standard design and may be purchased.23










Rev. #26: 12-01-19 062111 Page 7 of 26

Single-Phase, Subsurface, for New Construction (continued)

Table 8 Codes for Subsurface Subway-LB, Single-Phase, (reference Document 072139 and Spec. 91) −Self-Protected, Stainless Steel

kVA2,400/4,160Y-120/2403 Primary Bushings

4 Secondary Bushings

12,000/20,780Y − 120/240

2 Primary Bushings4 Secondary Bushings

3 Primary Bushings4 Secondary Bushings

50 261388 1, E 261384 1 261391 1

100 261389 1 261385 1, E 261392 1, E

167 261390 1, E 261386 1 261393 1

250 − 261387 1, E 261394 1, E

Three-Phase, Pad-Mount, for New Construction

Table 9 Codes for Duplex-Style DF, Three-Phase, Pad-Mount, No Loop Switch, With Transformer Switch With6 Primary Bushings and 4 Secondary Bushings Including the Insulated Neutral (referenceDocument 064307 and Spec. 86) − Self-Protected

kVA

12,000/20,780GrdY/12,000 17,200 20,780

240/120 V 240/120 V 240/120 V

Mild Steel Stainless Mild Steel Mild Steel

25/10 261547 1 − 261551 1 −

50/10 261548 1, E 262047 1, E 261552 1, E 261914 1, E

100/25 261549 1 − 261553 1 −

100/50 261550 1, E 262049 1, E 261554 1, E 261915 1, E

Table 10 Codes for Style MTP, Three-Phase, Pad-Mount With 6 Primary Bushings and 4 Secondary BushingsIncluding the Insulated Neutral (reference Document 045290 and Spec. 86) − Self-Protected

kVA

12,000/20,780GrdY/12,000 20,780

208Y/120 V 480Y/277 V 208Y120 V 480Y277 V

Mild Steel Stainless Mild Steel Stainless Mild Steel

45 261897 1 261909 1 261898 1 261910 1 261905 1 261906 1

150 261899 1 261911 1, E 261900 1 261912 1, E 261907 1, E 261908 1, E

Table 11 Codes for Style MTP, Three-Phase, Pad-Mount With 6 Primary Bushings and 4 Secondary BushingsIncluding the Insulated Neutral (reference Document 045290 and Spec. 86) − Self-Protected

kVA

4,160 17,200

208Y/120 V 480Y/277 V 208Y/120 V 480Y/277 V

Mild Steel Mild Steel

45 − − 261901 1 261902 1

150 262782 1, E 262783 1, E 261903 1, E 261904 1, E













Rev. #26: 12-01-19062111 Page 8 of 26

Three-Phase, Pad-Mount, for New Construction (continued)

Table 12 Codes for Style IIE-LB, No Loop Switches, With Transformer Switch With 6 Primary Bushings and 4 Secondary Bushings Including the InsulatedNeutral (reference Document 045290 and Spec. 86) − Self-Protected

kVA

4,160 x 12,000

208Y/120 V 480Y/277 V


75 261397 1 261401 1

150 261398 1 261402 1

300 261399 1, E 261403 1, E

750 261400 1, E 261404 1, E

Table 13 Codes for Style IIE-LB, No Loop Switches, With Transformer Switch With 6 Primary Bushingsand 4 Secondary Bushings Including the Insulated Neutral (reference Document 045290 andSpec. 86) (continued) − Self-Protected

kVA

12,000/20,780GrdY/12,000 12,000/20,780Y12,000

208Y/120 V 480Y/277 V 2,400/4,160Y/2,400 V 240/120 Delta

Mild Steel Stainless Mild Steel Stainless Mild Steel Stainless Mild Steel Stainless

75 261405 1 261443 1 261410 1 261446 1 − − − −

150 261406 1 263128 1 261411 1 263124 1 − − 261421 1 −

300 261407 1, E 261444 1, E 261412 1, E 261447 1, E − − 261422 1 262645 1, E

750 261408 1 263125 1 261413 1 263127 1 261417 1 − − −

1,000 261409 1, E 261445 1, E 261414 1, E 261448 1, E 261418 1 261450 1 − −

1,500 − − 261415 1 241619 1 261419 1 − − −

2,500 − − 261416 1 261449 1, E 261420 1 261451 1, E − −

Table 14 Codes for Style IIE-LB, No Loop Switches, With Transformer Switch With 6 PrimaryBushings and 4 Secondary Bushings Including the Insulated Neutral (referenceDocument 045290 and Spec. 86) (continued) − Self-Protected

kVA

17,200

208Y/120 V 480Y/277 V 2,400/4,160Y/2,400 V

Mild Steel Mild Steel Mild Steel

75 261423 1 261428 1 −

150 261424 1, E 261429 1, E −

300 261425 1 261430 1 −

750 261426 1, E 261431 1, E 261435 1, E

1,000 261427 1, E 261432 1 −

1,500 − 261433 1, E −

2,500 − 261434 1, E 261436 1, E











Rev. #26: 12-01-19 062111 Page 9 of 26


Table 15 Codes for Style IIE-LB, No Loop Switches, With Transformer Switch With 6 PrimaryBushings and 4 Secondary Bushings Including the Insulated Neutral (referenceDocument 045290 and Spec. 86) (continued) − Self-Protected

kVA

20,780

208Y/120 V 480Y/277 V

Mild Steel Stainless Mild Steel Stainless

75 261437 1 261452 1 261440 1 261454 1

150 261438 1 − 261441 1 −

300 261439 1 261453 1, E 261442 1 261455 1, E

Table 16 Codes for Style IIE-LB, With Three-Phase Loop Switches, With Transformer SwitchWith 6 Primary Bushings and 4 Secondary Bushings Including the Insulated Neutral(reference Document 045290 and Spec. 86) − Self-Protected

kVA

12,000/20,780GrdY/12,000

208Y/120 V 480Y/277 V


75 261456 1 − 261459 1 −

300 261457 1, E − 261460 1, E −

1,000 261458 1 261472 1, E 261461 1 261473 1, E

1,500 − − 261893 1 −

2,500 − − 261894 1 261895 1, E

Table 17 Codes for Style IIE-LB, With Three-Phase Loop Switches, With Transformer Switch With 6 Primary Bushings and 4 Secondary Bushings Including the Insulated Neutral(reference Document 045290 and Spec. 86) (continued) − Self-Protected

kVA

17,200 20,780

208Y/120 V 480Y/277 V 208Y/120 V 480Y/277 V

Mild Steel Mild Steel Mild Steel Mild Steel

75 261462 1 261465 1 261468 1 261470 1

300 261463 1, E 261466 1, E 261469 1, E 261471 1, E

1,000 261464 1, E 261467 1, E − −

2,500 − 261896 1, E − −











Rev. #26: 12-01-19062111 Page 10 of 26


Table 18 Codes for Radial Dead-Front, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 Secondary Bushings Including the Insulated Neutral (reference Document 043816 andSpec. 86) − Conventional

kVA

20,780

208Y/120 V 480Y/277 V


750 − − 263031 1, E −

1,000 263029 1 261523 1, E − 261524 1

1,500 − − 263033 1 −

2,500 − − 263035 1 261525 1, E

(See Table 42 on Page 16 for other three-phase radial DF.)

Table 19 Codes for Style IIG, Three-Phase, Pad-Mount With Vacuum Fault Interrupter, With 6 Primary Bushings,4 Secondary Bushings Including Insulated Neutral With Stainless Steel Cabinet and FR3 Insulating Fluid(reference Document 072146 and Spec. 86)

kVA

12,000/20,780Grd/12,000 12,000/20,780Grd/12,000 17,200 20,780

480Y/277 2,400/4160Y/2,400 480Y/2772,400/4160Y/

2,400 480Y/277

No Loop SwitchWith 2 Loop

Switches No Switch No Loop Switch

2955/3325 262702 1, E 262703 1, E 262704 1, E 262705 1, E 262706 1, E 262707 1, E

Table 20 Codes for Style IIC, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 Secondary BushingsIncluding the Insulated Neutral (reference Document 045290 and Spec. 86) − Self-Protected

kVA

4,160 x 12,000

208Y/120 V 480Y/277 V


1,500 − 260789 1

2,500 − 260791 1, E

(See Table 38 on Page 15 for other Style IIC.)

Three-Phase, Subsurface, for New ConstructionTable 21 Codes for Subsurface Duplex, Three-Phase With 6 Primary Bushings and 3 Hot Secondary

Leads or Insulated Spades. The Neutral is a Welded Spade. (reference Document 051776 andSpec. 91) − Self-Protected, Stainless Steel

kVA12,000/20,780GrdY/12,000 − 240/120 V 17,200 − 240/120 V

No Switch With Three-Phase Switch No Switch With Three-Phase Switch

25/10 262122 1 262131 1 262349 1 262348 1

50/10 262128 1, E 262132 1, E 262350 1, E 262354 1

75/15 − 262133 1 − 262355 1

100/25 262130 1 262134 1 262352 1 262356 1, E

100/50 262363 1, E 262318 1, E 262353 1, E 262357 1, E













Rev. #26: 12-01-19 062111 Page 11 of 26

Three-Phase, Subsurface, for New Construction (continued)Table 22 Codes for Subsurface UCD-LB, Three-Phase With Two, Three-Phase Loop Switches and With

Transformer Switches With 6 Primary Bushings and 3 Hot Secondary Bushings. The NeutralMay Be Permanently Grounded. (reference Document 039830 and Spec. 91) − Self-Protected,Stainless Steel

kVA4,160 x 12,000 12,000/20,780GrdY/12,000 17,200

208Y/120 V 480Y/277 208Y/120 480Y/277 208Y/120 480Y/277

150 261798 1 261800 1 261802 1 261806 1 261810 1 261813 1

300 261799 1, E 261801 1, E 261803 1, E 261807 1, E 261811 1 261814 1

750 262327 1, E 262332 1, E 261804 1 261808 1 261812 1, E 261815 1, E

1,000 − − 261805 1, E 261809 1, E − −

Specialty Transformers

Table 23 Codes for Subsurface Network, Three-Phase With 3 Primary Bushings and 3 SecondaryBushings With No Ground Switch, No Termination Chamber (reference Document 072137 andSpec. 91) − Conventional, Plate Steel

kVA 12,000 − 208Y/120 V 12,000 − 480Y/277 V 12,000X34,500GrdY/19920480Y/277 V

34,500GrdY/19,920480Y/277 V

300 262664 1 − − −

500 262665 1 − − −

750 262666 1 262667 1, T 262673 1 262671 1

1,000 − 262668 1, T 262674 1 262662 1

1,500 − 262669 1, T 262675 1 262672 1

2,000 − 262670 1, T 262676 1 262663 1

Table 24 Codes for Subsurface Network, Three-Phase With 3 Primary Bushings and 3 SecondaryBushings With Ground Switch and Termination Chamber (reference Document 072137 and Spec. 91) − Conventional, Plate Steel

kVA 12,000 − 208Y/120 V 12,000 − 480Y/277 V 12,000X34,500GrdY/19920480Y/277 V

34,500GrdY/19,920480Y/277 V

300 262407 4 − − −

500 262408 4 262410 4, T − −

750 262409 4, E 262411 4, T 262419 4 262415 4

1,000 − 262412 4, E, T 262420 4 262416 4

1,500 − 262413 4, T 262421 4 262417 4

2,000 − 262414 4, T 262422 4, E 262418 4

Table 25 Codes for Subsurface Vault, Three-Phase with 3 Primary Bushings and 3 Secondary 600A ESNABushings (Spec. 91).

kVA 12,000 x 34,500GrdY/19,920 − 4,160Y/2400 V

2,000 262889 1


4 Use for replacement only and may be purchased.E Included in Emergency StockT With high voltage taps.










Rev. #26: 12-01-19062111 Page 12 of 26

Specialty Transformers (continued)

Table 26 Codes for Dry-Type Network. Three-Phase With 3 Primary Bushings and3 Secondary Bushings − Conventional, 65/115� Rise Cast Coil, Rotated Layout

kVA 12,000 − 208Y/120 V 12,000 − 480Y/277 V 34,500GrdY/19,920480Y/277 V

500 262777 1, T − −

750 262778 1, T 262773 1, T 262779 1, T

1,000 − 262774 1, T 262780 1, T

1,500 − 262775 1, T −

2,000 − 262776 1, T 262781 1, T

Table 27 Codes for Dry-Type Network. Three-Phase With 3 Primary Bushings and3 Secondary Bushings − Conventional, 65/115� Rise Cast Coil, In-Line Layout

kVA 12,000 − 208Y/120 V 12,000 − 480Y/277 V 34,500GrdY/19,920480Y/277 V

500 − − −

750 − − 262816 1, T

1,000 − 262813 1, T 262817 1, T

1,500 − 262814 1, T −

2,000 − 262815 1, T 262818 1, T

Table 28 Codes for Pad-Mount Network, Three-Phase With 3 Primary Bushings and 3 Secondary Bushings(reference Document 045774 and Spec. 86) − Conventional, Mild Steel

kVA 12,000 - 480Y/277 V 34,500GrdY/19,920 - 480Y/277 V

750 260666 1 260655 1

1,000 260667 1 260656 1

1,500 260684 1 260657 1

2,000 260699 1 260658 1


4 Use for replacement only and may be purchased.E Included in Emergency StockT With high voltage taps





Rev. #26: 12-01-19 062111 Page 13 of 26

Specialty Transformers (continued)

Table 29 Codes for System Tie, Three-Phase, Pad-Mount With 3 Primary Bushings and 3 SecondaryBushings (reference Document 068184 and Spec. 86) − Conventional, Mild Steel

kVA

12,000/20,780GrdY/12,000 -4,160GrdY/2,400 V

0° Phase Shift @ 21 kV30° Phase Shift @ 12 kV

12,000−4,800

6,930/12,000Y - 4,160Y/2,400 V0° Phase Shift @ 12 kV

20780 -4,160GrdY/2,400 V

30° Phase Shift @ 21 kV

With One Recloser on Secondary Side

2,500 261381 1, E − 262578 1, E 262579 1, E

3,000 − 262696 1, E −

Table 30 Codes for System Tie, Three-Phase, Pad-Mount With 3 Primary Bushings and 3 SecondaryBushings (reference Document 051119 and Spec. 86) (continued) − Conventional, Mild Steel

kVA

20,780Y/12,000 17,200 V Delta

12,000Y/6,930 V 17,200 V Delta 12,000Y/6930 V

Without Recloser With 2 Reclosers30° Lead to 30° Lag Switch

With Recloser on 21 kV Side30° Lead to 30° Lag Switch

Without Recloser

3,600 264134 1 262661 1, E 261151 1, E, T

7,500 261943 1 262473 1, E 262573 1, E, T

Table 31 Codes for Pad-Mount, Grounding Bank, Three-Phase, (for cogeneration fault sensing with Hο bushing, 2.5% impedance) With 6 Primary Bushings and 3 Secondary Bushings (referenceDocument 062264 and Spec. 86) − Self-Protected, Mild Steel

kVA 20,780GrdY/12,000 - 480 V Delta

225 017072 1

Table 32 Codes for Zigzag - Radial Dead-Front, Three-Phase, Pad-Mount With 2 Primary Bushings and4 Secondary Bushings Including the Insulated Neutral (reference Document 045786 and Spec. 86) − Conventional, Mild Steel

kVA20,780GrdY/12,000

208Y/120 V 480Y/277 V

300 263073 1, E 263076 1, E

Single-Phase, Pad Mount, for Replacements Only

Table 33 Codes for Live-Front, Clam Shell, Single-Phase, Pad-Mount With 2 Primary Bushings and 2 HotSecondary Bushings. Neutral May Be Permanently Grounded. (reference Document 042761 andSpec. 86) − Self-Protected

kVA

With Single-Phase Cabinet

12,000GrdY/6,930 - 240/120 V 12,000/20,780 GrdY - 240/120 V

Mild Steel Mild Steel Stainless Steel

50 − 263002 4 263037 4

100 261274 4, E 263004 4, E 263038 4, E

167 261275 4, E 263016 4, E 263039 4


4 Use for replacement only and may be purchased.E Included in Emergency StockT With high voltage taps













Rev. #26: 12-01-19062111 Page 14 of 26

Single-Phase, Pad Mount, for Replacements Only (continued)Table 34 Codes for Live-Front, Clam Shell, Single-Phase, Pad-Mount With 3 Primary Bushings and 2 Hot

Secondary Bushings. Neutral May Be Permanently Grounded. (reference Document 042761 andSpec. 86) (continued) − Self-Protected

kVA

With Three-Phase Cabinet

12,000GrdY/6,930240/120

4,160X12,000240/120 V

12,000/20,780 GrdY −240/120 V

17,200240/120 V

20,780240/120 V

Mild Steel Mild Steel Mild Steel Stainless Steel Mild Steel Mild Steel

50 − 263014 4, E 263006 4, E 263040 4, E 263010 4, E 263044 4

100 261276 4, E 263015 4, E 263008 4, E 263041 4, E 263012 4, E 263045 4, E

167 261277 4, E 263019 4, E 263017 4, E 263042 4 263018 4, E 263046 4, E

Single-Phase, Subsurface Round, for Replacements Only

Table 35 Codes for Subsurface Round, Single-Phase, 3 Secondary Bushings With Insulated Neutral. Use asthe Power Transformer in the Bank. (reference Document 035313 and Spec. 91) − Self-Protected,Stainless Steel

kVA

4,160/7,200Y − 240/120 V4 Primary Bushings

4,160GrdY/2,400 − 240/120 V2 Primary Bushings

12,000/20,780GrdY240/120 V

4 Primary Bushings

17,200 − 240/120 V4 Primary Bushings

No SwitchWith

Single-PhaseSwitch

No SwitchWith

Single-PhaseSwitch

No Switch No Switch

25 262362 4 E 262316 4 − − − −

50 − − − − − 262314 4

75 − − 262328 4 − − −

100 − − − − 262283 4, E −

167 − − − − 262284 4, E −

Table 36 Codes for Subsurface Round Single-Phase With 3 Secondary Bushings, Neutral May Be PermanentlyGrounded. Use to Supply Single-Phase Load or as the Lighting Transformer in a Bank. (reference Document 035313 and Spec. 91) − Self-Protected, Stainless Steel

kVA

4,160/7,200Y240/120 V4 PrimaryBushings

4,160GrdY/2,400240/120 V

2 Primary Bushings

12,000/20,780GrdY240/120 V

4 Primary Bushings

12,000/20,780GrdY480/240 V

4 Primary Bushings

No Switch No SwitchWith

Single-PhaseSwitch

No SwitchWith

Single-PhaseSwitch

No Switch

25 − − − − − 262307 1, E

50 − − − 262058 4, E 262096 4, E −

75 − − − − − 262324 4, E

100 (see Table 7 on Page 6) 262060 4, E 262098 4, E −

167 262372 4, E 262121 4, E 262144 4 262062 4, E 262099 4, E −











Rev. #26: 12-01-19 062111 Page 15 of 26

Single-Phase, Subsurface Round, for Replacements Only (continued)

Table 37 Codes for Subsurface Round, Single-Phase With 3 Secondary Bushings, Neutral May Be PermanentlyGrounded. Use to Supply Single-Phase Load or as the Lighting Transformer in a Bank.(reference Document 035313 and Spec. 91) (continued) − Self-Protected, Stainless Steel

kVA

12,000GrdY/6,930240/120 V

2 Primary Bushings

17,200240/120 V

4 Primary Bushings

20,780GrdY/12,000240/120 V

2 Primary Bushings

20,780GrdY/12,000480/240 V

2 Primary Bushings

No SwitchWith

Single-PhaseSwitch

No Switch No Switch

WithSingle-PhaseSwitch

No Switch

WithSingle-PhaseSwitch

25 − − − − − 262321 1, E 262303 1, E

50 262054 4, E 262090 4, E 262186 4, E 262147 4, E 262153 4, E − −

100 262056 4, E 262092 4, E 262188 4, E 262149 4, E 262155 4, E − −

167 262086 4, E 262093 4, E 262189 4, E 262150 4, E 262156 4, E − −

Three-Phase, Pad-Mount, for Replacements OnlyTable 38 Codes for Style IIC*, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 Secondary Bushings

Including the Insulated Neutral (reference Document 045290 and Spec. 86) − Self-Protected

kVA

4,160X12,000

480Y/277 V

Mild Steel

1,500 260789 1

2,500 260791 1, E

(Style IIC and Style llF transformers are completely interchangeable except for the primary fuses.)*See Table 20 on Page 10 for others of this type.

Table 39 Codes for Style IIF, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 Secondary BushingsIncluding the Insulated Neutral (reference Document 045290 and Spec. 86) − Self-Protected

kVA

12,000/20,780GrdY/12,000

208Y/120 480Y/277 2,400/4,160Y/2,400

Mild Steel Stainless Steel Mild Steel Stainless Steel Mild Steel Stainless Steel

300 261284 4, E − 261288 4 262115 4, E − −

750 261285 4 − 261289 4 − − −

1,000 261286 4, E 262114 4 261290 4 262116 4, E 261292 4 −

1,500 − − 261291 4 − 261293 4 −

2,500 − − 261328 4 262177 4, E 261329 4 262179 4, E0











Rev. #26: 12-01-19062111 Page 16 of 26

Three-Phase, Pad-Mount, for Replacements Only (continued)Table 40 Codes for Style IIF, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 Secondary Bushings

Including the Insulated Neutral (reference Document 045290 and Spec. 86) (continued) − Self-Protected

kVA

4,160X12,000 17,200

208Y/120 480Y/277 208Y/120 480Y/277


300 261281 4 261283 4 − 261296 4

750 261287 4, E 261282 4, E 261294 4 261297 4

1,000 − − 261295 4, E 261298 4, E

1,500 − − − 261299 4

2,500 − − − 261330 4, E

Table 41 Codes for Style IIH, Three-Phase, Pad-Mount, Live-Front With Vacuum Fault Interrupter, with 3 PrimaryBushings and 4 Secondary Bushings With Insulated Neutral With Stainless Steel Cabinet and FR3Insulating Fluid (reference Document 072146 and Spec. 86)

kVA

12,000/20,780GrdY/12,000 17,200

480Y/277 2,400/4160Y/2,400 480Y/277


2955/3325 262708 4, E 262709 4, E 262710 4, E

Table 42 Codes for Radial, Dead-Front*, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 SecondaryBushings Including the Insulated Neutral (reference Document 043816 and Spec. 86) (continued) −Conventional

kVA

12,000/20,780GrdY/12,000 17,200

208Y/120 V 480Y/277 V 480Y/277 V


75 260315 4 260314 4 −

150 260732 4 260317 4 −

300 260682 4 260326 4 −

750 260080 4, E 260039 4, E 260880 4, E

1,000 260107 4, E 260041 4 260181 4

1,500 − 260002 4 260883 4, E

2,500 − 260042 4, E −* See Table 18 on Page 10 for others of this type.


4 Use for replacement only and may be purchased.E Included in Emergency Stock









Rev. #26: 12-01-19 062111 Page 17 of 26

Three-Phase, Pad-Mount, for Replacements Only (continued)Table 43 Codes for Radial, Live-Front, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 Secondary

Bushings Including the Insulated Neutral (reference Document 043816 and Spec. 86) − Conventional

kVA

4,160X12,000 17,200208Y/120 V 480Y/277 V 208Y/120 V 480Y/277 V


75 260695 4 − 260309 4 260613 4

150 − − − 260615 4

300 − − 260289 4 260617 4

750 260921 4 − − −

Table 44 Codes for Radial, Live-Front, Three-Phase, Pad-Mount With 3 Primary Bushings and 4 SecondaryBushings Including the Insulated Neutral (reference Document 043816 and Spec. 86) (continued) −Conventional

kVA

12,000/20,780GrdY/12,000208Y/120 V 480Y/277 V


75 260710 4 260764 4

150 260755 4 260766 4

300 260757 4 260768 4

750 260759 4 260770 4, E

1,000 260760 4, E −

1,500 − 260677 4

2,500 − 260773 4, E

Table 45 Codes for Subsurface Vault, Three-Phase With 3 Primary Bushings and 4 Secondary BushingsIncluding the Insulated Neutral (reference Document 072138 and Spec. 91) − Conventional,Plate Steel

kVA 12,000/20,780GrdY/12,000 − 208Y/120 V 12,000/20,780GrdY/12,000 − 480Y/277 V

300 262428 4 −

750 262430 4 262432 4

1,000 262107 4, E 262433 4, E

1,500 − 262434 4

2,500 − 015641 4, E


4 Use for replacement only and may be purchased.E Included in Emergency Stock









Rev. #26: 12-01-19062111 Page 18 of 26

Designation of Voltage Ratings of Windings - Single-Phase Transformers

Table 46 Designation of Voltage Ratings of Windings − Single-Phase Transformers

Item Designation Typical VoltageRating

Typical WindingDiagram Description

1 E 12,000 Indicates a winding of E volts which is suitablefor delta connection on an E volt system.

2 E/E1Y 1 2,400/4,160YIndicates a winding of E volts which is suitablefor delta connection on an E volt system or forwye connection on an E1 volt system.

3 E/E1Grd.Y 112,000/20,780 Grd. Y

or2,400/4,160 Grd.Y

Indicates a winding of E volts having insulationsuitable for delta connection on an E volt systemor for wye connection on an E1 volt effectivelygrounded system.

4 E1Grd.Y/E 120,780 Grd. Y/12,000

or12,000 Grd. Y/6,930

Indicates a winding of E volts which has oneend of the winding grounded internally. Windingswith one end grounded internally are suitable forsingle-phase or wye operation on a three-phaseE1 volt effectively grounded system.

5 E/2E120/240

or240/480

Indicates a winding, the sections of which canbe connected in parallel for operation at E volts,connected in series for operation at 2E volts, orconnected in series with a center terminal for3-wire operation at 2E volts between the extreme terminals and E volts between the center terminal and each of the extreme terminals.

6 2E/E 240/120

Indicates a winding having a mid-tap and suitable for 3-wire operation at 2E volts betweenextreme terminals and at E volts between themid-tap and each of the extreme terminals(not reconnectable).

1 E1 � 3� E



Rev. #26: 12-01-19 062111 Page 19 of 26

Designation of Voltage Ratings of Windings − Three-Phase Transformers

Table 47 Designation of Voltage Ratings of Windings − Three-Phase Transformers

Item Designation Typical VoltageRating

Typical WindingDiagram Description

7 E 12,000Indicates a winding that is permanentlydelta connected for operation on an E volt system.

8 E1Grd.Y/E 1

20,780Grd.Y/12,000

or34,500

Grd.Y/19,920

Indicates a winding that is permanentlywye connected with neutral grounded tothe tank for operation on an E1 volt effectively grounded system with E voltsavailable from line to neutral.

9 E/E1Grd.Y/E 1 12,000/20,780Grd.Y/12,000

Indicates a winding which may be deltaconnected for operation on an E volt system or may be wye connected for operation on an E1 volt grounded systemwith E volts available from line to neutral.

10

V x V1

4,160 x 12,000Indicates a permanently delta connectedwinding for multiple or series operation.

11 12,000 x 34,500Grd. Y/19,920

Indicates a winding which may be deltaconnected for operation on a 12 kVsystem or wye connected for operation ona 34.5 kV effectively grounded wye system.

1 E1 � 3� E

Table 48 Transformer Insulating Fluid Material Codes

FR3 High-Fire PointNatural Ester

BioTemp High-Fire Point Natural Ester

Mineral Oil SiliconeHigh-Fire Point

National Standard ASTM D6871 ASTM D6871 ASTM D3487 ASTM D4652

5 Gallon Pail M507033

55 Gallon Drum M500046 M507034 M500043

Bulk M507017



Rev. #26: 12-01-19062111 Page 20 of 26

Primary Voltages

Table 49 System Primary Voltages 1

Phase Primary Voltages System

Single-Phase 2,400/4,160Y For 2.4 kV - L-L Connection

Single-Phase 2,400 x 4,800 For 2.4 kV - L-L Connection

Single-Phase 4,160/7,200Y For 4 kV - L-L Connection

Single-Phase 4,160GrdY/2,400 For 4 kV - 4-Wire L-G Connection

Single-Phase 4,160 x 12,000 For 4 kV - L-L Connection

Single-Phase 4,160 x 7,200 For 4 kV - L-L Connection

Single-Phase 7,200/12,470Y For 12 kV - 4-Wire L-G Connection

Single-Phase 12,000 For 12 kV L-L or 21 kV L-G Connection

Single-Phase 12,000/20,780 GrdY For 12 kV L-L or 21 kV L-G Connection

Single-Phase 12,000/20,780Y For 12 kV L-L or 21 kV L-G Connection


Single-Phase 12,470GrdY/7,200 For Use in Chester

Single-Phase 17,200 For 17 kV L-L Connection

Single-Phase 20,780 For 21 kV L-L Connection


Single-Phase 24,940GrdY/14,400 For Use in Chester

Single-Phase 44,000 For 44 kV - L-L Connection

Single-Phase 44,000/25,400 For 44 kV - L-L Connection

Three-Phase 4,160 For 4 kV - Delta Connection

Three-Phase 4,160GrdY/2,400 For 4 kV - 4-Wire L-G Connection

Three-Phase 4,160 x 12,000 For 4 kV - Delta Connection

Three-Phase 4,160 x 12,480 For 4 kV - Delta Connection

Three-Phase 12,000 For 12 kV - Delta Connection

Three-Phase 12,000/20,780GrdY/12,000 For 12 kV Delta or 21 kV GrdY Connection

Three-Phase 12,000 x 20,780 For 12 kV Delta or 21 kV Delta Connection

Three-Phase 12,000 x 34,500GrdY/19,920 For 12 kV or 34.5 kV Networks

Three-Phase 17,200 For 17 kV Delta Connection

Three-Phase 20,780 For 21 kV Delta Connection

Three-Phase 20,780GrdY/12,000 For 21 kV GrdY Connection

Three-Phase 20,780Y/12,000 For 21 kV Y Connection

Three-Phase 34,500GrdY/19,920 For 34.5 kV Networks1 Table 49 is intended to be a reference between the transformer’s primary voltage and the type of primary system that

it can be used on in the PG&E system.



Rev. #26: 12-01-19 062111 Page 21 of 26

Pictorial Index1

Box Style

1-Wire Cabinet 2-Wire Cabinet

3-Wire Cabinet

Clam Shell Single-Phase Cabinet Front Views (hinged tops open)

Front View(hinged top open)

Clam Shell Three-Phase Cabinet

Front View(hinged top open)

Single-Phase - Style Dead-Front

Front View(doors removed)

Style MTP and Duplex Style DF

Figure 1Single-Phase, Pad-Mount Transformers for Loop or Radial Application



Rev. #26: 12-01-19062111 Page 22 of 26

Pictorial Index (continued)

Style IIB 225 − 1,000 kVA

Style IIC 1,500 − 2,500 kVA

Style IID 75 − 300 kVA


CL Fuses InterlockedWith Switch




Bayonet Fuses

Style IIE 75 − 2,500 kVA


Style IIA

Style IIF 300 − 2,500 kVA

Bayonet Fuses

Figure 2Three-Phase, Pad-Mount Transformers for Loop or Radial Application



Rev. #26: 12-01-19 062111 Page 23 of 26



Style IIH 2955/3325 kVA

Figure 3Three-Phase, Pad-Mount Transformers for Loop or Radial Application

Style IIG 2955/3325 kVA

Vacuum Fault InterrupterOperating Handle

Vacuum Fault InterrupterOperating Handle



Rev. #26: 12-01-19062111 Page 24 of 26


Dead-Front Radial



12 − 21 kV Tie Autotransformer


Pad-Mounted Network Transformer

Open Wye to Zigzag Wye


Fence Enclosed

Live-Front Radial


Figure 4Three-Phase, Pad-Mount Transformers for Radial Application



Rev. #26: 12-01-19 062111 Page 25 of 26


Front View

Three-Phase, Subsurface, Duplex Horizontal

Neutral Spade

Single-Phase, Subsurface Horizontal - 4-Bushing Single-Phase, Subsurface Round-Type

Single-Phase, Subsurface Horizontal - 6-Bushing

Insulated Neutral

Three-Phase UCD Transformer

Figure 5Subsurface Transformers for Loop or Radial Application

Three-Phase UCD−LB Transformer

SubmersibleBayonet Fuses



Rev. #26: 12-01-19062111 Page 26 of 26


Three-Phase Subsurface Vault

Three-Phase Network Transformer With ProtectorSingle-Phase Subsurface SubwaySubway−LB

Figure 6Subsurface Transformers for Radial Application

Revision Notes

Revision 26 has the following changes:

1. Updated Tables 19 and 20 on Page 10.

Documents

062111 - Application of Underground Distribution Transformers...Bushings and 3 Secondary Bushings Including the Insulated Neutral (see ANSI/IEEE Type 2(a) per IEEE C57.12.25) − Self-Protected